In carrier Ethernet networks, it is required to provide link and node redundancy for certain network topologies including, for example: 1) a dual-homed access node linked to two provider edge (PE) devices—such as a customer edge (CE) or a digital subscriber line access multiplexer (DSLAM) linked to two PE devices—and 2) an access network linked to two provider edge (PE) devices. The two PE devices typically may feed into an aggregation or core network.
There are a number of existing mechanisms available to achieve redundancy for the above topologies. These require, however, the access (e.g., typically a customer of the provider) node or nodes to be running some type of specialized protocol. For example, a customer device (e.g., CE or DSLAM on the access side) typically configures one of its uplink ports as primary while the other is configured as backup so that failure of the primary causes a switchover to the backup link. In this scheme, the provider PE devices do not run any protocol. Consequently, the PE nodes have no control over the link selection or switchover.